IC-card service period setting method, IC card, IC card case and battery charger

ABSTRACT

A method of setting validity period of IC card, includes preparing IC card including change unit whose state changes with lapse of time starting from initial state without external power, measuring unit configured to measure state of change unit so as to generate information indicating whether or not validity period has elapsed, and operation unit configured to be operable if information indicates that validity period fails to have yet elapsed, and to be inoperable if information indicates that validity period has elapsed, preparing IC card case capable to house IC card by user, IC card case including identification unit configured to determine whether or not user is legitimate, performing user identification utilizing identification unit, when IC card is housed in IC card case, and transmitting signal to change unit in IC card depending on result of user identification, signal initializing change unit to initial state.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of priorityfrom U.S. Ser. No. 10/720,100, filed Nov. 25, 2003, and is based uponand claims the benefit of priority from the prior Japanese PatentApplication No. 2003-023220, filed Jan. 31, 2003, the entire contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an IC card and an IC card case devisedto prevent illegal use and battery charger for supplying power to the ICcard case.

2. Description of the Related Art

Integrated circuit (IC) cards have come to be used in various fields asemployee ID cards, club member ID cards, insurance ID cards, etc., inaddition to business transaction cards, such as credit cards and debitcards. Since IC cards are equipped with a CPU, ROM, RAM, EEPROM, etc.,which are not incorporated in conventional magnetic cards, they can havevarious functions and are hard to forge, which significantly enhancestheir security. Therefore, IC cards are often used to store personalinformation (see, for example, Jpn. Pat. Appln. KOKAI Publication No.2001-312711).

Attention has recently been paid to power analysis attacks against ICcards. In these attacks, the key used in an encryption scheme, such asDES and RSA, which is often utilized when IC cards are identified by acard reader, is found by analyzing the power consumed while thedecryption algorithm is being executed. Such methods as the above forattacking IC cards without opening the cards have greatly advanced.

As described above, IC cards are hard to forge and hence have come to bewidely used to store personal information, while IC card attackingmethods have greatly advanced. Therefore, if an IC card is lost andacquired by a third party, it can be used illegally, resulting inserious damage.

As a countermeasure to cope with, for example, an IC card being lost andacquired by a third party, the amount of money that can be transacted ina single month is limited, or the number of occasions the card can beused is limited. However, this is not a fundamental solution forpreventing illegal use when an IC card is lost. As anothercountermeasure, some IC cards have a built-in timer for limiting theperiod of the validity of the card. In this case, however, a powersupply must be incorporated in the card to allow the timer to operatecontinuously, which is a serious problem for IC cards, as theirspecifications are limited.

BRIEF SUMMARY OF THE INVENTION

The preset invention has been developed in light of the above, and aimsto provide an IC card and IC card case that can prevent their illegaluse without a power supply, even if they are lost, simply by changingthe data stored in the card and/or the structure of the card.

According to a first aspect of the invention, there is provided a methodof setting a validity period of an IC card, comprising: preparing an ICcard including a change unit whose state changes with lapse of timestarting from an initial state without an external power, a measuringunit configured to measure the state of the change unit so as togenerate information indicating whether or not the validity period haselapsed, and an operation unit configured to be operable if theinformation indicates that the validity period fails to have yetelapsed, and to be inoperable if the information indicates that thevalidity period has elapsed; preparing an IC card case capable to housethe IC card by a user, the IC card case including an identification unitconfigured to determine whether or not the user is legitimate;performing user identification utilizing the identification unit, whenthe IC card is housed in the IC card case; and transmitting a signal tothe change unit in the IC card depending on a result of the useridentification, the signal initializing the change unit to the initialstate.

According to a second aspect of the invention, there is provided an ICcard unusing a built-in power supply and driven by an external powersupplied from an external device when the IC card is connected to theexternal device, the IC card comprising: a change unit whose statechanges with lapse of time starting from an initial state without theexternal power; a measuring unit configured to measure the state of thechange unit so as to generate information indicating whether or not aperiod has elapsed; and an operation unit configured to be operable ifthe information indicates that the period fails to have yet elapsed, andto be inoperable if the information indicates that the period haselapsed.

According to a third aspect of the invention, there is provided an ICcard case capable to house an IC card by a user, the IC card startingmeasurement of a period in response to an instruction and continuing themeasurement without an external power, the IC card being usable if theperiod fails to have elapsed and being unusable if the period haselapsed, the IC card case comprising: an identification unit configuredto determine whether or not the user is legitimate; a performing unitconfigured to perform user identification utilizing the identificationunit, when the IC card is housed in the IC card case; and a transmissionunit configured to transmit a signal to the IC card depending on aresult of the user identification, the signal initializing the IC cardto the initial state.

According to a fourth aspect of the invention, there is provided acharger to be connected to an IC card case to charge a battery unitprovided in the IC card case capable to house an IC card by a user, thebattery unit being configured to issue an instruction to the IC card,the IC card starting measurement of a period in response to theinstruction, and continuing the measurement without an external power,the IC card being usable if the period fails to have elapsed and beingunusable if the period has elapsed, the charger comprising: adetermination unit configured to determine whether or not the IC cardcase is a preset IC card case, when the IC card case is connected to thecharger; and a charging unit configured to charge the battery unit ifthe determination unit determines that the IC card case is the preset ICcard case.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 illustrates the whole system according to an embodiment of theinvention;

FIG. 2 is a block diagram illustrating the configuration of an IC cardreader 1 used in the embodiment;

FIG. 3 is a block diagram illustrating the configuration of an IC card 2used in the embodiment;

FIG. 4 is a block diagram illustrating the basic concept of an agingdevice 37;

FIG. 5 is a block diagram illustrating a first example for realizing theaging device 37;

FIG. 6 illustrates changes in the state of an aging device 37-1 withlapse of time;

FIG. 7 is a graph illustrating the relationship between the time and theoutput signal of the aging device 37-1;

FIG. 8 is a block diagram illustrating a second example for realizingthe aging device 37;

FIG. 9 is a block diagram illustrating a third example for realizing theaging device 37;

FIG. 10 is a block diagram illustrating the structure of the agingdevice 37;

FIG. 11 is a block diagram illustrating another example of the agingdevice 37;

FIG. 12 is a block diagram illustrating an IC card case 3 used in theembodiment;

FIG. 13 is a flowchart useful in explaining the operation of housing theIC card 2 into the IC card case 3;

FIG. 14 is a flowchart useful in explaining the operation of ejectingthe IC card 2 from the IC card case 3 to use it;

FIG. 15 is a flowchart useful in explaining the operation of permittinga user to use the IC card 2; and

FIG. 16 is a block diagram illustrating a charger 6.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the invention will be described in detail withreference to the accompanying drawings.

FIG. 1 illustrates the whole system according to the embodiment.

In this system, an IC card service provider provides services through anIC card 2. The owner of the IC card 2, who can utilize the services,stores it in an IC card case 3 when the owner does not utilize theservices. On the other hand, to utilize the services, the owner takesthe card 2 out of the card case 3 and inserts it into an IC card reader1 owned by the IC card service provider.

A database 4 stores and manages data concerning IC card owners whoutilize the services, in a centralized manner. In the embodiment, thedatabase 4 stores at least an ID and cipher key assigned to each IC card2, in relation to each other.

A large number of IC card readers 1 are provided by the IC card serviceprovider, and connected to the database 4 via a network 5. In the caseof the services that are provided only at a particular place, it is amatter of course that the IC card reader 1 may store the database 4 andthe network 5 may not be used.

FIG. 2 is a block diagram illustrating the configuration of the IC cardreader 1.

In FIG. 2, a contact unit 21 is an interface that is electricallyconnected to the IC card 2 when the IC card 2 is inserted in the IC cardreader 1, and exchanges data with the IC card 2. An input unit 22 isused when the owner of the IC card 2 inputs a password or any otherdata. A power supply unit 23 supplies power to the IC card 2 via thecontact unit 21 when the IC card 2 is inserted.

A password identification unit 24 reads a password from the IC card 2via the contact unit 21, thereby determining whether or not the readpassword is identical to that input from the input unit 22, to confirmthe legitimacy of the user. If they are determined to be identical, anallowance signal is output to a cipher key acquisition unit 25.

Upon receiving the allowance signal from the password identificationunit 24, the cipher key acquisition unit 25 reads an ID from the IC card2 via the contact unit 21, thereby issuing a request to the database 4via a communication unit 26, using the ID, and acquiring therefrom thecipher key uniquely corresponding to the ID.

A card identification unit 27 utilizes the cipher key acquired by thecipher key acquisition unit 25, to confirm the legitimacy of theinserted IC card 2. This identification process will be described later.

A power supply 28 is supplied with an external AC power supply andsupplies power to the each internal element of the IC card reader 1. Thepower supply unit 23 is also supplied with power from the power supply28.

An IC card owner who utilizes IC card services carries the IC card 2,and inserts the card 2 into the IC card reader 1 when the IC card ownerutilizes the services.

FIG. 3 is a block diagram illustrating the configuration of the IC card2.

In FIG. 3, a contact unit 31 is exposed on the outer surface of the ICcard 2 so that it is electrically connected to the contact unit 21 ofthe IC card reader 1 when the IC card 2 is inserted in the IC cardreader 1. When the IC card 2 is inserted in the IC card reader 1, poweris supplied from the power supply unit 23 of the IC card reader 1 to thepower supply unit 38 of the IC card 2 via the contact unit 31. The powersupply unit 38 supplies each element in the IC card 2.

A process unit 32 performs various procedures while services are beingutilized in the IC card 2.

A password storage 33 stores a password for using the IC card 2. Ingeneral, passwords are stored in IC cards 2 when the cards 2 aredistributed to users. An ID storage 34 stores an ID from which the ICcard 2 is identified. In general, IDs are stored in IC cards 2 when thecards 2 are manufactured. A cipher key storage 35 stores a cipher keyassigned to the IC card 2. Generally, cipher keys are stored in IC cards2 when the cards 2 are distributed to users.

A card identification unit 36 cooperates with the card identificationunit 27 to determine whether or not the IC card 2 is used by alegitimate user, when the IC card 2 is inserted in the IC card reader 1.

An aging device 37 can determine whether or not a predetermined timeperiod has elapsed. When the aging device 37 operates, it is notnecessary to supply power thereto. When the aging device 37 is suppliedwith power (device charging power) via the contact unit 31 from the ICcard case 3 described later, it starts time measurement. The agingdevice 37 is referred to by the card identification unit 36, when the ICcard 2 is connected to the IC card reader 1 and the card identificationunit 36 performs identification.

The aging device 37 will now be described in detail.

FIG. 4 is a block diagram illustrating the basic concept of the agingdevice 37. The aging device 37 comprises a change unit 41, the state ofwhich changes with lapse of time without a power supply, such asbattery; an input unit 42 for inputting an input signal to the changeunit 41; and an output unit 43 for outputting an output signal changedrelative to the input signal based on the state of the change unit 41.The change in the state of the change unit 41 is utilized to measuretime. The input unit 42 and output unit 43 are used to confirm the stateof the change unit 41.

FIG. 5 is a block diagram illustrating a first example for realizing theaging device 37 of FIG. 4.

The aging device 37-1 comprises: a first layer having a source region51, drain region 52 and channel region 53 therebetween; a second layerprovided on the first layer and formed of a tunnel insulation film 54; athird layer provided on the second layer and formed of a floating gate55; a fourth layer provided on the third layer and formed of aninsulation film 56; and a fifth layer provided on the fourth layer andformed of a control gate 57. A source electrode 58 and drain electrode59 are provided on the source and drain regions 51 and 52, respectively.

FIG. 6 illustrates changes with lapse of time in the state of the agingdevice 37-1 of FIG. 5. In the figure, hatched circles indicateelectrons, and white circles indicate positive holes.

In FIG. 6, state 1 is the initial state. In the aging device 37-1 thatassumes the state 1, a pre-process is performed, in which the controlgate 57 applies a high electric field between the substrate boundary ofthe channel region 53 and the floating gate 55, thereby injectingelectrons from the channel into the floating gate 55 utilizing FNtunneling. At this time, positive holes gather at the substrate boundaryof the channel region 53, whereby a channel is defined at the substrateboundary between the source and drain regions 51 and 52.

In the state 1, the electrons in the floating gate 55 gradually shift,by direct tunneling, to the substrate boundary, thereby reducing thelevel of the electric field at the substrate boundary in the channelregion 53. State 2 of FIG. 6 is the state assumed at a time point T₁ acertain time period after the state 1. State 3 of FIG. 6 is the stateassumed at a time point T₂ a certain time period after the state 2.Similarly, state 4 is the state assumed at a time point T₃ a certaintime period after the state 3. The circles indicated by the broken linesrepresent the shift of electrons made due to direct tunneling by therespective time points. In the state 4 at the time point T₃, mostelectrons escape from the floating gate 55, therefore the channel at thesubstrate boundary of the channel region 53 disappears. As a result, nosignals are output.

FIG. 7 is a graph illustrating the relationship between the time and theoutput signal of the aging device 37-1. Direct tunneling occurs betweentime points T_(a)(=0) and T_(b), and lastly, the channel disappears,whereby the level of the output signal is reduced to the noise level.Since the aging device 37-1 supplies an output signal corresponding to achange in level between T_(a)(=0) and T_(b)(=the time when the outputsignal level reaches the noise level), the side for receiving the outputsignal can determine whether or not a predetermined time period haselapsed, or can determine a specific time point (e.g. T₁, T₂ or T₃ shownin FIG. 7) a predetermined time period after the initial state if therelationship between the state of the aging device 37-1 and the level ofthe output signal is always clear. The time points T₁, T₂ and T₃correspond to the states 2, 3 and 4 in FIG. 6.

FIG. 8 is a second example 37-2 that realizes the aging device 37 ofFIG. 4. The aging device 37-2 comprises: a first layer having a sourceregion 61, drain region 62 and channel region 63 therebetween; a secondlayer provided on the first layer and formed of a tunnel insulation film64; a third layer provided on the second layer and formed of a gate 65;and a PN junction 66 provided on the third layer for controlling a leakcurrent. A source electrode 68 and drain electrode 69 are provided onthe source and drain regions 61 and 62, respectively.

The change in the state of the aging device 37-2 with lapse of time issimilar to that of the aging device 37-1, although in the former,current leakage occurs in a PN junction, and in the latter, directtunneling occurs. Therefore, no description is given of the change inthe state of the aging device 37-2 with lapse of time.

FIG. 9 is a third example 37-3 that realizes the aging device 37 of FIG.4. The aging device 37-3 comprises: a first layer having a source region71, drain region 72 and channel region 73 therebetween; a second layerprovided on the first layer and formed of a tunnel insulation film 74; athird layer provided on the second layer and formed of a gate 75; and aSchottky junction 76 provided on the third layer for controlling a leakcurrent. A source electrode 78 and drain electrode 79 are provided onthe source and drain regions 71 and 72, respectively.

The change in the state of the aging device 37-3 with lapse of time issimilar to that of the aging device 37-1, although in the former,current leakage occurs in a Schottky junction, and in the latter, directtunneling occurs. Therefore, no description is given of the change inthe state of the aging device 37-3 with lapse of time.

As described above, a pre-process for forming a channel is needed beforetime measurement is started by the aging device 37. In the embodiment,the pre-process is performed only when charging power is supplied fromthe IC card case 3 to the aging device 37.

Referring now to FIG. 10, the structure of the aging device 37 thatincorporates the above-described change unit 41 will be described.

In FIG. 10, a voltage can be applied between the opposite ends of thechange unit 41. A power supply terminal 81 is connected to the sourceelectrode 58, 68, 78 of the aging device 37 via a switch element 83,while a GND terminal 82 is connected to the drain electrode 59, 69, 79via an ampere meter 84.

The switch element 83 is connected to an ON/OFF (enable) signal linethat only instantly outputs an ON signal when the supply of power to theIC card 2 starts at the contact unit 31. This signal is turned on whenan ON signal is supplied.

The ampere meter 84 is connected to output a current value to acomparator 85. The comparator 95 receives a current value at one inputterminal, and a predetermined threshold value at the other inputterminal, and outputs a signal of the “H” or “L” level depending uponwhether or not the current value is higher than the predeterminedthreshold value. The output of the comparator 85 is stored in a stateregister 86. The state register 86 is connected so that the cardidentification unit 36 can refer to it. When data concerning the stateof the aging device 37 is stored in the state register 86, the cardidentification unit 36 turns on the switch element 83 to thereby apply apredetermined voltage between the power supply terminal 81 and GNDterminal 82. The current flowing through the change unit 41 is measuredby the ampere meter 84, the measured current value is converted into the“L” or “H” level by the comparator 85, and the resultant “L” or “H”level is stored as the above-mentioned data. To refer to the state ofthe aging device 37, the card identification unit 36 reads dataconcerning the state of the aging device 37 from the state register 86.

In the above example, a single change unit 41 is employed. However, theaging device 37 may incorporate a plurality of change units 41. FIG. 11illustrates an aging device 37 in which a plurality of change units 41is arranged in parallel, and the current values output from the units 41are input to an averaging circuit 87, thereby comparing the averagedcurrent value with the threshold by the comparator 85 and storing the“L” or “H” level in the state register 86. The ON/OFF (enable) signalline is connected to the respective switch elements 83 so that theswitch elements 83 are commonly controlled. In this example, even if thechange units 41 exhibit some different changes in state with lapse oftime, their average value enables a stable aging device 37 to berealized.

The IC card case 3 will now be described.

The owner of the IC card 2 uses the IC card case 3 to house the IC card2 therein when the owner does not use the card. One IC card case isassigned to each IC card 2. In other words, only if the IC card uniquelycorresponding to an IC card case is inserted therein, the IC card caseoperates normally. FIG. 12 is a block diagram illustrating theconfiguration of an IC card case 3.

A contact unit 91 is exposed on the inner surface of the IC card case 3so that it is electrically connected to the contact unit 31 of the ICcard 2 when the IC card 2 is housed in the IC card case 3.

A cipher key storage 92 stores a cipher key assigned to the IC card 2. Acard identification unit 39 cooperates with the card identification unit36 of the IC card 2 to determine whether or not the IC card 2corresponds to the IC card case 3 when the IC card 2 is housed in the ICcard case 3. This mutual identification process may be performedutilizing, for example, the transmission protocol stipulated in theISO/IEC7816 series. If the card identification unit 93 determines thatthe IC card 2 is legitimate, it informs a card lock unit 97 of this.

A password storage 94 stores a password. If this password is setidentical to that of the IC card 2, the usability of the IC card case 3is enhanced, while if the former is set different from the latter, thesecurity is enhanced. Thus, it is advisable to set the password storedin the storage 94 according to purpose.

An input unit 95 is used by a user to input the password so as to ejectthe IC card 2 from the IC card case 3. The password identification unit96 compares the input password with the stored one to determine thelegitimacy of the user. If the password identification unit 96determines that the user is legitimate, it informs the card lock unit 97and aging activation unit 98 of this.

When it is informed by the card identification unit 93 that the card islegitimate, the card lock unit 97 locks an IC card ejection mechanism(not shown). Further, when it is formed by the password identificationunit 96 that the user is legitimate, the card lock unit 97 unlocks theIC chard ejection mechanism. The IC card case 3 may be modified suchthat the card identification unit 96 informs the card lock unit 97 of auser even if the user is determined to be illegitimate, and the cardlock unit 97 does not unlock the IC card ejection mechanism for apredetermined time period even if the user is determined legitimateafter they have been determined illegitimate several successive times.This structure further enhances the security.

The aging activation unit 98 supplies aging-device-charging power to theIC card 2 via the contact unit 91 if the password identification unit 96determines that the user is legitimate. This charging power is suppliedusing a terminal different from that used to drive each element in theIC card 2.

A power supply 99 is, for example a battery for supplying power, and isused to supply power to each element in the IC card case 3 and to eachelement in the IC card 2 via the contact unit 91.

A description will be given of operations, performed by the systemconstructed as above, for housing the IC card 2 into the IC card case 3,ejecting the IC card 2 from the IC card case 3, and using the IC card 2in the IC card reader 1.

Firstly, referring to FIG. 13, the operation of housing the IC card 2into the IC card case 3 will be described.

After using the IC card 2, the user inserts the IC card 2 into the ICcard case 3 (S11).

When the IC card 2 is inserted in the IC card case 3, mutualidentification is performed by the card identification unit 36 of the ICcard 2 and the card identification unit 93 of the IC card case 3 (S12).As above-mentioned, this mutual identification process is performedutilizing, for example, the transmission protocol stipulated in theISO/IEC7816 series.

If the card identification unit 93 of the IC card case 3 determines thatthe IC card 2 is legitimate, it informs the card lock unit 97 of this(S13). Upon receiving the information, the card lock unit 97 locks theejection mechanism for ejecting the IC card 2 (S14).

On the other hand, if the card identification unit 93 of the IC cardcase 3 determines that the IC card 2 is illegitimate, the IC card 2 isforcedly ejected from the case by the ejection mechanism (S15).

The above procedure enables only the IC card uniquely corresponding toan IC card case to be stored therein.

Referring to FIG. 14, a description will be given of the operation ofejecting the IC card 2 from the IC card case 3 to use the card.

When a user utilizes the IC card 2, the user firstly inputs a passwordfor identification through the input unit 95 of the IC card case 3(S21). The input password is sent to the password identification unit96, where it is compared with the password read from the passwordstorage 94 (S22).

If it is determined from the comparison that the two passwords are notidentical to each other, nothing is performed. This means that the cardlock unit 97 keeps the ejection mechanism locked, therefore the IC card2 cannot be ejected.

If, on the other hand, it is determined at the step S22 that the twopasswords are identical, this is reported to the aging activation unit98, which, in turn, charges the aging device 37 via the contact unit 91(S23).

After that, the password identification unit 96 informs the card lockunit 97 that the two passwords are determined to be identical at thestep S22, whereby the card lock unit 97 releases the ejection mechanism(S24) to permit the IC card 2 to be ejected (S25).

Referring then to FIG. 15, the operation of permitting a user to use theIC card 2 will be described.

Firstly, the user inserts the IC card 2 into the IC card reader 1 (S31).In this state, the IC card 2 is charged with power by the IC card reader1. Upon the supply of power from the card reader 1 to the card 2, an ONsignal is supplied to the aging device 37, whereby the aging device 37stores data indicative of the present state of the change unit 41 in thestate register (S32).

Subsequently, the user inputs the password of the IC card 2 to the ICcard reader 1 through the input unit 22 (S33). The passwordidentification unit 24 of the IC card reader 1 reads the password fromthe password storage 33 of the IC card 22, and compares the readpassword with the input password to determine whether or not they areidentical (S34). If they are not identical, it is determined that theuser is illegitimate, thereby making it impossible to use the IC card 2(S35). At this time, for example, an error message is generated and theIC card 2 is ejected.

On the other hand, if the passwords are determined to be identical atthe step S34, the cipher key acquisition unit 25 reads an ID from the IDstorage 34 of the IC card 2 (S36), thereby issuing a request for acipher key to the database 4 via the communication unit 26, using the ID(S37). As a result, the cipher key uniquely corresponding to the ID isacquired from the database 4 (S38). The acquired cipher key istransferred to the card identification unit 27.

After that, the card identification unit 36 of the IC card 2 refers tothe state of the aging device 37, and determines whether or not thestate of the aging device 37 indicates the elapse of a predeterminedtime period (S39). If it is determined that the state of the agingdevice 37 indicates the elapse of the predetermined time period, theprogram proceeds to a step S35, whereas if the state of the aging device37 indicates the elapse of a time period shorter than the predeterminedtime period, the program proceeds to a step S40.

Further, if the state of the aging device 37 indicates the elapse of thepredetermined time period, the card identification unit 36 of the ICcard 2 may perform a process for changing part or the whole portion of amessage that is used for identification and is sent to the cardidentification unit 27 of the IC card reader 1. Alternatively, the unit36 may send no message. In other words, if the state of the aging device37 indicates the elapse of the predetermined time period, the cardidentification unit 36 may make it impossible to perform a correctidentification process between the IC card reader 1 and IC card 2.

Thereafter, the card identification unit 27 cooperates with the IC cardidentification unit 36 of the IC card 2 to perform mutual identification(S40), utilizing, for example, the transmission protocol stipulated inthe ISO/IEC7816 series.

If identification has succeeded at the step S40, services are provided(S41). If identification has failed at the step S40, the use of the ICcard 2 is prohibited (S35). Of course, there may be a case whereidentification has failed at the step S40 for reasons other than thereason that the aging device 37 indicates the elapse of thepredetermined time period.

The period of validity can be set in the above-described IC card 2 ofthe embodiment without providing the card with a power supply, such as abattery. Further, when the IC card 2 is ejected from a card caseuniquely corresponding to the card, it is checked whether or not alegitimate user tries to use the card 2, and then measurement of theperiod of use is started. Therefore, in light of the required period ofuse, the period of the validity of the card can be set to a relativelyshort period. When the period of validity is set short, even if the card2 is lost and acquired by a third party, the possibility of illegal useby the third party is reduced because the period of validity will soonbe expired. Thus, the security is enhanced.

Further, after the expiration of a set period of validity, a legitimateuser can use the IC card 2 again simply by charging the IC card 2 by theIC card case 3, without a complicated operation (for example, accessingthe service company to ask the resumption of use).

In the embodiment, the function of making it impossible to use the ICcard 2 after the expiration of the period of validity determined by theaging device 37 is realized by the card identification unit 36 thatutilizes the information, on the state of the aging device 37, held inthe state register. The embodiment of the invention is not limited tothis, but may be modified in various ways. For example, the power supplyunit 38 may control the supply of power to each element based on thecontents of the state register. Alternatively, a switch may be providedacross the line between each element and the contact unit 31, therebyperforming ON/OFF control of the switch.

Furthermore, in the embodiment, the aging device 37 is charged via thecharging terminal of the contact unit 91. However, a message (commandfor IC cards) for an identification process between the IC card 2 and ICcard case 3 (performed using the transmission protocol stipulated in theISO/IEC7816 series) can be utilized to charge the aging device 37.Although the format of the message is determined by the protocol, partof the message can be set by a vender. Accordingly, the instruction tocharge the aging device 37 may be contained in the message sent from theIC card case 3 to the IC card 2, thereby making the power supply unit 38of the IC card 2 charge the aging device 37.

Although in the embodiment, the user identification is performedutilizing password identification, another identification system, suchas fingerprint identification or biological identification, can beutilized.

Also, in the embodiment, the protocol used for the card identificationprocess between the IC card 2 and IC card reader 1 is also used for thatbetween the IC card 2 and IC card case 3. However, a dedicated protocolmay be used for the card identification process between the IC card 2and IC card case 3, since it does not influence the existing IC cardsystems.

In addition, in the embodiment, the IC card 2 is inserted into the ICcard reader 1, and their contact units are connected. However, theconnection method is not limited to this. For example, the IC card 2 andIC card reader 1 may have their respective coils capable of receivingelectromagnetic waves, so that they can be connected to each other outof contact with each other.

The above-described IC card system has been devised to consider the casewhere only the IC card 2 is lost. Since, however, the IC card case 3 isalso carried by an IC card owner, it is possible to lose the IC cardcase 3 with the IC card housed therein. In light of this, the powersupply 99 of the IC card case 3 may be constructed such that it ischarged only by the charger dedicated thereto. By virtue of thisstructure, the security is further enhanced. Lastly, a modification, inwhich this structure is added to the above-described embodiment, will bedescribed.

FIG. 16 is a block diagram illustrating a charger 6.

The charger 6 has the same shape as the IC card 2, and is constructedsuch that an AC cord 102 is exposed to the outside when the charger 6 isattached to the IC card case 3.

As shown in FIG. 16, to attach the charger 6 to the IC card case 3, acontact unit 101 is opposed to the contact unit 91 of the IC card case3. When the charger 6 is attached to the IC card case 3, the contactunits 101 and 91 are electrically connected.

A cipher key storage 104 stores the same cipher key as that for the ICcard 2.

A card identification unit 103 cooperates with the card identificationunit 93 of the IC card case 3 to determine whether or not the IC cardcase 3 uniquely corresponds to the charger 6 when they are attached toeach other. The card identification unit 103 transmits and receivesmessages, using the cipher key stored in the cipher key storage 104, andperforms identification using the transmission protocol stipulated inthe ISO/IEC7816 series. If the card identification unit 103 determinesthat the IC card case 3 is legitimate, it permits AC power to besupplied from the AC cord 102, connected to an AC power supply (notshown), to the IC card case 3 via the contact unit 101. The power supply99 of the IC card case 3 is charged with the AC power. If it isdetermined as a result of mutual identification that the IC card case 3is illegitimate, no power is supplied from the AC cord 102 to thecontact unit 101.

As described above, the charger 6 employed in the modification chargesthe IC card case 3 after the legitimacy of the case is confirmed by cardidentification. Even if the IC card case 3 with the IC card 2 housedtherein is lost and a third party acquires it, the third party cannotillegally utilize the IC card 2. This is because the power remaining inthe IC card case 3 is consumed while the third party is trying to ejectthe card 2 from the case 3 by repeatedly inputting random passwords, andbecause once the power has been consumed, no further power can becharged in the power supply 99 of the IC card case 3, thereby preventingillegal use of the IC card 2.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

1. An IC card case configured to house an IC card by a user, the IC cardstarting measurement of a period in response to an instruction andcontinuing the measurement without an external power, the IC card beingusable if the period fails to have elapsed and being unusable if theperiod has elapsed, the IC card case comprising: an identification unitconfigured to determine whether or not the user is legitimate; aperforming unit configured to perform user identification utilizing theidentification unit, when the IC card is housed in the IC card case, theIC card including a change unit whose state changes with lapse of timestarting from an initial state without an external power, a measuringunit configured to measure the state of the change unit so as togenerate information indicating whether or not the validity period haselapsed, and an operation unit configured to be operable if theinformation indicates that the validity period fails to have yetelapsed, and to be inoperable if the information indicates that thevalidity period has elapsed; and a transmission unit configured totransmit a signal to the IC card depending on a result of the useridentification, the signal initializing the IC card to the initialstate.
 2. The IC card case according to claim 1, further comprising: anejection unit configured to eject the IC card from the IC card case; anda lock unit configured to lock the IC card in the IC card case, the lockunit being released after the signal is transmitted to the IC card. 3.The IC card case according to claim 1, further comprising: an ejectionunit configured to eject the IC card from the IC card case; adetermination unit configured to determine whether or not the IC card isa preset IC card when the IC card is housed into the IC card case; and alock unit configured to lock the IC card in the IC card case if thedetermination unit determines that the IC card is the preset IC card,the lock unit being released after signal is transmitted to the IC card.